The present invention relates, in general, to an axial bearing unit.
Nothing in the following discussion of the state of the art is to be construed as an admission of prior art.
U.S. Pat. No. 5,335,998 describes an axial bearing unit having two bearing disks with radial sections to form raceways for rolling elements received in a cage. Both radial sections of the bearing disks are formed about their inner peripheral edge with an axial collar, whereby the collar of one radial section and the collar of the other radial section oppose one another, and one collar embraces the other collar. Each of the bearing disks has a central bore, whereby the bores of the both bearing disks have different diameter. The bearing disks are held together by providing the collar of the bearing disk of smaller bore diameter with a retaining lug which is directed radially outwards and engages behind the collar of the other bearing disk. For reasons of lubrication, the collar of the bearing disk of smaller bore diameter is provided with recesses which are evenly spaced about the circumference of the collar. The provision of such recesses allows only very limited lubrication of the axial bearing unit because lubricant can enter from the outside into the bearing interior only via a very narrow gap. In other words, the flow of lubricant must overcome substantial resistance from the bearing unit.
It would therefore be desirable and advantageous to provide an improved axial bearing unit to obviate prior art shortcomings and to improve lubrication.